To improve the durability and washability of ultraviolet (UV) protective fabrics, grafted polymer brushes are introduced as platforms for in-situ growth of zinc oxide (ZnO) nanostructure on modified cotton fibres, using the electroless deposition approach. Hollow cotton fibre acts as a micro-reactor for ZnO deposited on both inner and outer surfaces. More importantly, adjusting the reaction in a micro-environment enable effective control of the morphology of ZnO crystals and the functionalized fabric shows durable UV blocking properties. Unlike other finishing processes, the functional ZnO nanocrystals are grown not only on the surface of the fibres but also inside of the hollow cotton fibres but with different morphology. This unique property of the post-modification allows the functional fabrics to show good antifriction capability, washability, and durability. The combination of the zinc oxide and the textiles brings out new features for plain cloth, and the final product can be applied to outdoor clothing, protective suits, tents, and curtains, etc.